Social Exclusion Changes Brain Function

"Our findings indicate that social rejection can be a powerful influence on how people act," said W. Keith Campbell, a psychologist who led the research. Researchers have known for a long time that there is a link between social exclusion and the failure of self-control. The new study, however, is the first to use magnetoencephalography (MEG) to show that there are actual changes inside the brain when test subjects are manipulated to feel socially excluded.

The subjects in the current study were 30 women undergraduates in a psychology course at UGA. Each one was asked to complete a written personality questionnaire. The team leading the experiment then said they would "feed the answers into a computer," which was, in fact, untrue. Instead, half of the sample, selected randomly, was told their answers showed they would "end up alone" later in life. The others were given a more neutral assessment of their social interactions.

"At this point, we gave each of the subjects a series of simple mathematical problems, taking 25 minutes, to solve on a computer screen in front of them while they were in the MEG machine," said Campbell. "We presented participants with 180 problems, and what we found was surprising." The MEG data revealed that those in the social-exclusion group had clear differences in activity in the brain's occipital, parietal and prefrontal cortex regions. Those in the social-exclusion group also performed more poorly on the math questions. The inference is that social exclusion actually affects the brain's neural circuitry.

The parietal cortex is involved in attention, while the prefrontal cortex helps support so-called "executive functioning" processes such as working memory and other behaviours that may support self control. "We found that there was a direct link between social exclusion, brain activity and performance," said Campbell.